Re: [PATCH 3/8] generic/050: fix ro blockdev mount of xfs with quota

[Eryu Guan <guaneryu@gmail.com>]

On Tue, Nov 27, 2018 at 03:19:55PM -0800, Darrick J. Wong wrote:
> On Sun, Nov 04, 2018 at 11:32:36PM +0800, Eryu Guan wrote:
> > On Thu, Nov 01, 2018 at 04:19:21PM -0700, Darrick J. Wong wrote:
> > > From: Darrick J. Wong <darrick.wong@oracle.com>
> > > 
> > > In XFS, mounting with quota always require a writable device.  If the
> > > block device is read only, the mount fails, which fails this test.
> > > Since this is expected, work around this.
> > > 
> > > Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
> > > ---
> > >  tests/generic/050 |   23 +++++++++++++++++++----
> > >  1 file changed, 19 insertions(+), 4 deletions(-)
> > > 
> > > 
> > > diff --git a/tests/generic/050 b/tests/generic/050
> > > index 90e924db..33da228d 100755
> > > --- a/tests/generic/050
> > > +++ b/tests/generic/050
> > > @@ -36,6 +36,21 @@ _require_norecovery
> > >  
> > >  _scratch_mkfs >/dev/null 2>&1
> > >  
> > > +filter_ro_mount() {
> > > +	local arg=""
> > > +
> > > +	# Mounting with quota on XFS requires a writable fs, which means
> > > +	# we fail the ro blockdev test with with EPERM.
> > > +	if [ "$FSTYP" = "xfs" ] && echo "$MOUNT_OPTIONS" | grep -q quota ; then
> > > +		arg="s|mount: $SCRATCH_MNT: permission denied|mount: device write-protected, mounting read-only|g"
> > > +	fi
> > > +	sed -e "$arg" | _filter_ro_mount
> > > +}
> > > +
> > > +filter_umount() {
> > > +	sed -e "\|umount: $SCRATCH_DEV: not mounted.|d" | _filter_scratch
> > > +}
> > > +
> > >  #
> > >  # Mark the device read-only
> > >  #
> > > @@ -46,7 +61,7 @@ blockdev --setro $SCRATCH_DEV
> > >  # Mount it, and make sure we can't write to it, and we can unmount it again
> > >  #
> > >  echo "mounting read-only block device:"
> > > -_try_scratch_mount 2>&1 | _filter_ro_mount
> > > +_try_scratch_mount 2>&1 | filter_ro_mount
> > >  
> > >  echo "touching file on read-only filesystem (should fail)"
> > >  touch $SCRATCH_MNT/foo 2>&1 | _filter_scratch
> > 
> > This touch expects a failure message, but with this change applied, test
> > still failed when testing with "-o usrquota,grpquota,prjquota" mount
> > options as
> > 
> >     --- tests/generic/050.out   2018-07-01 20:36:05.796146192 +0800
> >     +++ /root/workspace/xfstests/results//generic/050.out.bad   2018-11-04 23:25:34.551700377 +0800
> >     @@ -3,7 +3,6 @@
> >      mounting read-only block device:
> >      mount: device write-protected, mounting read-only
> >      touching file on read-only filesystem (should fail)
> >     -touch: cannot touch 'SCRATCH_MNT/foo': Read-only file system
> 
> Hmm, what kernel is this on?  I've never seen this problem, but maybe I
> just have too many patches everywhere. :/

I cannot remember.. But I think the problem here is that, ro mount with
quota failed but we amended & hid the failure by filter_ro_mount, then
the 'touch' expected a ro-mounted fs, but it actually created a new file
on rootfs without hitting the EROFS error.

Thanks,
Eryu